1. Field of the Invention
The present invention relates to a computer technology for refining a plurality of logical volumes to a smaller number of logical volumes.
2. Description of the Related Art
Technology for providing a plurality of logical storage devices (logical volumes) on one or more physical storage devices (e.g. hard disks) has already been known. From such a plurality of logical volumes, one or more logical volumes can be selected. This may be performed, for example, in a computer system where a plurality of operational host computers (hereafter called “operational host (s)”), one or more management host computers (hereafter called “management host (s)”), and one or more storage sub-systems further comprising a plurality of logical volumes (e.g. RAID system) are connected to such a communication network as a SAN (Storage Area Network). Specifically, for example, an administrator selects one or more logical volumes from a plurality of logical volumes for each operational host using the management host, and allocates the selected logical volumes to the operational host. In this case, the administrator selects seemingly appropriate logical volumes based on experiment, considering the purpose of the operational host and the attributes on the logical volume (e.g. storage capacity and RAID type).
However, for a human to select from a plurality of logical volumes based on their judgment is a burden, and increases operation cost. Because the number of logical volumes to be provided as choices is in some cases enormous, a logical volume allocation operation for each operational host may be required to be performed frequently.
As a technology to solve such problems, a technology disclosed in Japanese Patent Application Laid-Open No. H5-108425 is available, that is, a computer retrieves logical volumes having predetermined logical volume attributes, such as open storage capacity and input/output load, from the plurality of logical volumes, and presents the retrieved logical volumes to the administrator as volume candidates.